scholarly journals New Insights Into the Antibacterial Mechanism of Cryptotanshinone, a Representative Diterpenoid Quinone From Salvia miltiorrhiza Bunge

2021 ◽  
Vol 12 ◽  
Author(s):  
Bo-Chen Chen ◽  
Zhi-Shan Ding ◽  
Jian-Sheng Dai ◽  
Ni-Pi Chen ◽  
Xing-Wen Gong ◽  
...  
Keyword(s):  
Respiratory Chain ◽  
Antimicrobial Agents ◽  
Salvia Miltiorrhiza ◽  
Membrane Vesicles ◽  
Redox Balance ◽  
Docking Study ◽  
Synergistic Activity ◽  
Metabolome Analysis ◽  
Molecular Docking Study ◽  
Wide Range

The rapid rise of antibiotic resistance causes an urgent need for new antimicrobial agents with unique and different mechanisms of action. The respiratory chain is one such target involved in the redox balance and energy metabolism. As a natural quinone compound isolated from the root of Salvia miltiorrhiza Bunge, cryptotanshinone (CT) has been previously demonstrated against a wide range of Gram-positive bacteria including multidrug-resistant pathogens. Although superoxide radicals induced by CT are proposed to play an important role in the antibacterial effect of this agent, its mechanism of action is still unclear. In this study, we have shown that CT is a bacteriostatic agent rather than a bactericidal agent. Metabolome analysis suggested that CT might act as an antibacterial agent targeting the cell membrane. CT did not cause severe damage to the bacterial membrane but rapidly dissipated membrane potential, implying that this compound could be a respiratory chain inhibitor. Oxygen consumption analysis in staphylococcal membrane vesicles implied that CT acted as respiratory chain inhibitor probably by targeting type II NADH:quinone dehydrogenase (NDH-2). Molecular docking study suggested that the compound would competitively inhibit the binding of quinone to NDH-2. Consistent with the hypothesis, the antimicrobial activity of CT was blocked by menaquinone, and the combination of CT with thioridazine but not 2-n-heptyl-4-hydroxyquinoline-N-oxide exerted synergistic activity against Staphylococcus aureus. Additionally, combinations of CT with other inhibitors targeting different components of the bacterial respiratory chain exhibit potent synergistic activities against S. aureus, suggesting a promising role in combination therapies.

Design, Synthesis, Antimicrobial and Anti-biofilm Evaluation, and Molecular Docking of Newly Substituted Fluoroquinazolinones

2019 ◽  
Vol 15 (6) ◽  
pp. 659-675
Author(s):  
Mohamed F. Zayed ◽  
Sabrin R.M. Ibrahim ◽  
EL-Sayed E. Habib ◽  
Memy H. Hassan ◽  
Sahar Ahmed ◽  
...  
Keyword(s):  
Molecular Docking ◽  
Antimicrobial Agents ◽  
Receptor Site ◽  
Docking Study ◽  
Diffusion Method ◽  
Molecular Docking Study ◽  
Active Compounds ◽  
Highly Active ◽  
Strong Binding ◽  
Agar Disc

Background: Quinazolines and quinazolinones derivatives are well known for their important range of therapeutic activities. Objective: The study aims to carry out the synthesis of some derivatives of substituted fluoroquinazolinones based on structure-based design and evaluation of their antibacterial, antifungal, and anti-biofilm activities. Methods: Compounds were chemically synthesized by conventional methods. Structures were established on the basis of spectral and elemental analyses. The antimicrobial potential was tested against various microorganisms using the agar disc-diffusion method. MIC and MBC as well as anti-biofilm activity for the highly active compounds were assessed. Moreover, the computational studies were performed using Auto dock free software package (version 4.0) to explain the predicted mode of binding. Results: All derivatives (5-8), (10a-g), and (A-H) were biologically tested and showed significant antimicrobial activity comparable to the reference compounds. Compounds 10b, 10c, and 10d had a good MIC and MBC against Gram-positive bacteria, whereas 10b and 10d showed significant MIC and MBC against Gram-negative bacteria. However, compounds E and F exhibited good MIC and MBC against fungi. Compound 10c and 8 exhibited significant anti-biofilm activity towards S. aureus and M. luteus. Molecular docking study revealed a strong binding of these derivatives with their receptor-site and detected their predicted mode of binding. Conclusion: The synthesized derivatives showed promising antibacterial, antifungal, and antibiofilm activities. Modeling study explained their binding mode and showed strong binding affinity with their receptor-site. The highly active compounds 5 and 10c could be subjected to future optimization and investigation to be effective antimicrobial agents.

scholarly journals New Benzoxazole Derivatives as Antiprotozoal Agents: In Silico Studies, Synthesis, and Biological Evaluation

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Mohamed A. Abdelgawad ◽  
Mohammad M. Al-Sanea ◽  
Mohamed A. Zaki ◽  
Enas I. A. Mohamed ◽  
Shabana I. Khan ◽  
...  
Keyword(s):  
Antimicrobial Agents ◽  
Antimalarial Activity ◽  
Biological Activities ◽  
Docking Study ◽  
Antimicrobial Activities ◽  
Biological Evaluation ◽  
Molecular Docking Study ◽  
Chromatographic Separations ◽  
Major Mechanism ◽  
In Silico Studies

Background. Benzoxazole derivatives have different biological activities. In pursuit of designing novel chemical entities with antiprotozoal and antimicrobial activities, benzoxazolyl aniline was utilized as a privileged scaffold of a series of (3-benzoxazole-2-yl) phenylamine derivatives, 3-benzoxazoloyl acetamide, and butyramide derivatives. Methods. These novel analogs were synthesized in straightforward simple chemistry without any quantitative chromatographic separations in reasonable yields. The biological evaluation of all target compounds as potential antimalarial, antileishmanial, antitrypanosomal, and antimicrobial agents was performed by various well-established cell-based methods. Results. Compounds 6d and 5a showed promising biological screening data. The amidation of 3-benzoxazolyl aniline 1 with the chloroacetyl functional group resulted in a good antimalarial activity and showed moderate inhibitory activities against leishmanial and trypanosomal spp. Moreover, chloroacetyl functionalization of benzoxazolyl aniline serves as a good early goal for constructing and synthesizing new antimicrobial and antiprotozoal agents. The molecular docking study rationalizes the relative inhibitory activity of compound 5a as an antimalarial agent with the deregulation of PfPNP activity which has emerged as a major mechanism of these targets.

Synthesis and molecular docking study of some 3,4-dihydrothieno[2,3-d]pyrimidine derivatives as potential antimicrobial agents

2019 ◽  
Vol 88 ◽  
pp. 102934 ◽  
Author(s):  
Omaima G. Shaaban ◽  
Doaa A.E. Issa ◽  
Alaa A. El-Tombary ◽  
Shrouk M. Abd El Wahab ◽  
Abeer E. Abdel Wahab ◽  
...  
Keyword(s):  
Molecular Docking ◽  
Antimicrobial Agents ◽  
Docking Study ◽  
Pyrimidine Derivatives ◽  
Molecular Docking Study

scholarly journals SYNTHESIS, MOLECULAR MODELING, AND QUANTITATIVE STRUCTURE–ACTIVITY RELATIONSHIP STUDIES OF UNDEC-10-ENEHYDRAZIDE DERIVATIVES AS ANTIMICROBIAL AGENTS

2017 ◽  
Vol 10 (16) ◽  
pp. 94
Author(s):  
Manju Kumari ◽  
Rakesh Narang ◽  
Surendra Kumar Nayak ◽  
Sachin Kumar Singh ◽  
Vivek Gupta ◽  
...  
Keyword(s):  
Antimicrobial Activity ◽  
Antimicrobial Agents ◽  
Docking Study ◽  
Quantitative Structure Activity Relationship ◽  
Side Chain ◽  
Quantitative Structure ◽  
Molecular Docking Study ◽  
Qsar Studies ◽  
Structure Activity ◽  
Methoxy Groups

Objective: In recent years, an increasing frequency and severity of antimicrobial resistance to different antimicrobial agents, demands new remedies for the treatment of infections. Therefore, in this study, a series of undec-10-enehydrazide derivatives were synthesized and screened for in vitro activity against selected pathogenic microbial strains.Methods: The synthesis of the intermediate and target compounds was performed by standard procedure. Synthesized compounds were screened for antimicrobial activity by tube dilution method. Molecular docking study of synthesized derivatives was also performed to find out their interaction with the target site of β-ketoacyl-acyl carrier protein synthase III, (FabH; pdb id:3IL7) by docking technique. Quantitative structure–activity relationship (QSAR) studies were also performed to correlate antimicrobial activity with structural properties of synthesized molecules.Results: Antimicrobial screening results showed that compound 8 having benzylidine moiety with methoxy groups at meta and para position and compound 16 having 3-chloro-2-(3-flourophenyl)-4-oxoazetidine moiety was found to be most potent. QSAR studies revealed the importance of Randic topology parameter (R) in describing the antimicrobial activity of synthesized derivatives. Molecular docking study indicated hydrophobic interaction of deeply inserted aliphatic side chain of the ligand with FabH. The N-atoms of hydrazide moiety interacts with Ala246 and Asn247 through H-bonding. The m- and p-methoxy groups form H-bond with water and side chain of Arg36, respectively.Conclusion: Compound 8 having benzylidine moiety with methoxy groups at meta and para position and compound 16 having 3-chloro-2-(3- flourophenyl)-4-oxoazetidine moiety was found to most potent antibacterial and antifungal compounds, respectively.

scholarly journals Putative SARS-CoV-2 Mpro Inhibitors from an In-House Library of Natural and Nature-Inspired Products: A Virtual Screening and Molecular Docking Study

Molecules ◽  
2020 ◽  
Vol 25 (16) ◽  
pp. 3745 ◽  
Author(s):  
Stefania Mazzini ◽  
Loana Musso ◽  
Sabrina Dallavalle ◽  
Roberto Artali
Keyword(s):  
Molecular Docking ◽  
Virtual Screening ◽  
Chemical Space ◽  
Structural Diversity ◽  
Docking Study ◽  
Binding Pocket ◽  
Molecular Docking Study ◽  
Screening Experiments ◽  
Good Ability ◽  
Wide Range

A novel coronavirus (severe acute respiratory syndrome coronavirus 2, SARS-CoV-2) has been the cause of a recent global pandemic. The highly contagious nature of this life-threatening virus makes it imperative to find therapies to counteract its diffusion. The main protease (Mpro) of SARS-CoV-2 is a promising drug target due to its indispensable role in viral replication inside the host. Using a combined two-steps approach of virtual screening and molecular docking techniques, we have screened an in-house collection of small molecules, mainly composed of natural and nature-inspired compounds. The molecules were selected with high structural diversity to cover a wide range of chemical space into the enzyme pockets. Virtual screening experiments were performed using the blind docking mode of the AutoDock Vina software. Virtual screening allowed the selection of structurally heterogeneous compounds capable of interacting effectively with the enzymatic site of SARS-CoV-2 Mpro. The compounds showing the best interaction with the protein were re-scored by molecular docking as implemented in AutoDock, while the stability of the complexes was tested by molecular dynamics. The most promising candidates revealed a good ability to fit into the protein binding pocket and to reach the catalytic dyad. There is a high probability that at least one of the selected scaffolds could be promising for further research

Synthesis, Biological Evaluation and Molecular Docking Study of Pyrazole, Pyrazoline Clubbed Pyridine as Potential Antimicrobial Agents

2020 ◽  
Vol 18 (3) ◽  
pp. 306-314 ◽  
Author(s):  
Nisheeth C. Desai ◽  
Darshita V. Vaja ◽  
Krunalsinh A. Jadeja ◽  
Surbhi B. Joshi ◽  
Vijay M. Khedkar
Keyword(s):  
Antimicrobial Activity ◽  
Molecular Docking ◽  
Antimicrobial Agents ◽  
Docking Study ◽  
Biological Evaluation ◽  
Mass Spectral Data ◽  
Molecular Docking Study ◽  
Mass Spectral ◽  
Chemical Structures ◽  
Subunit B

Introduction: In continuation of our efforts to find new antimicrobials, herein we report the synthesis of various pyrazole, pyrazoline, and pyridine based novel bioactive heterocycles (3a-t). Methods: Newly synthesized compounds were analysed for their antimicrobial activity. Compounds 3c, 3h, 3i, 3k, 3n, and 3q showed significant antimicrobial activity. Results: Molecular docking study for the most active analogues against DNA gyrase subunit b (PDB ID: 1KZN) corroborated well with the observed antimicrobial potency exhibiting significant binding affinity. Conclusion: Interpretation of the chemical structures reported in this paper was based on IR, 1H NMR, 13C NMR, and mass spectral data.

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